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<html lang="en">
<head>
    <meta charset="UTF-8">
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    <title>Document</title>
</head>
<body>
    <script>
        var arr = [[1,2,3],[4,5,6],[7,8,9]];
		var arr1 = arr.flat()
		console.log(arr1) //[1, 2, 3, 4, 5, 6, 7, 8, 9]
		//排序
		// arr1.sort(function(a,b){
		// 	return b-a
		// })
		// console.log(arr1) //[9, 8, 7, 6, 5, 4, 3, 2, 1]

    </script>
</body>
</html>